产品中心

By Phil McKenna A plan to build a gigantic dam across the mouth of the Red Sea that could generate huge amounts of clean, renewable energy has been condemned by experts who say it would wreak untold ecological ruin. The scheme would literally part the Red Sea with a massive wall more than 150 metres high, one kilometre thick and 100 km long, stretching between Yemen in the north and either Eritrea or Djibouti in the south. Details of the proposed dam are published in the current issue of International Journal of Global Environmental Issues (DOI: 10.1504/IJGENVI.2007.016114). “There are huge pros and huge cons on this project,” admits study co-author Jaap Hanekamp of the Roosevelt Academy in Middelburg, Netherlands. “On the one hand, it would have huge ecological consequences. On the other hand, you generate huge amounts of electricity – without CO2 – for an impoverished region.” The study suggests such a dam would yield more than twice the energy of China’s Three Gorges Dam, which spans the Yangtze River in central China. It would generate 50 gigawatts of what Hanekamp and colleagues call “heliohydroelectric” power. It works by allowing the sun to lower the water level inside the dam through evaporation. Water allowed back into the closed sea then turns turbines to generate electricity, says Hanekamp. “This would be daring, absolutely, but this project definitely could be done,” he says. Hanekamp adds that such projects must be considered, since traditional renewable sources such as wind and solar cannot keep up with annual increases in energy demand. Other experts, however, argue that the sheer scale of ecological damage that the project could cause makes it inconceivable. “This is a completely ludicrous proposal,” says Peter Bosshard, policy director of the International Rivers Network, an organisation based in Berkeley, California, devoted to mitigating the harm caused by dams. “I’m trying to determine if this is serious or if this is meant as a parody of obsolete macro-engineering thinking. It reminds me of when the Soviets tried to play God by drying out the Aral Sea,” Bosshard says. The project would transform the Red Sea into a briny pool, reducing the 450,000 km2 sea by one third after 50 years and by two thirds after nearly 300 years, according to the study. Furthermore, by keeping water from the world’s oceans from flowing into the Red Sea – effectively reducing the area of the world’s oceans by 450,000 km2 – global sea levels would rise by 12 cm over the project’s first 50 years and by 30 cm after 291 years. That 12 cm increase is equal to 20 years’-worth of sea level rise due to global warming based on the current rate of increase. “I don’t think 50 gigawatts of dirty coal would raise sea levels by as much as their project would,” Bosshard says. Energy production wouldn’t start for 50 years, after the closed off sea dropped by 100 metres, at which time the project would yield 18 or 19 GW of energy. To reach peak power production, engineers would have to wait 291 years, until the sea’s water level had dropped by 611 metres, before reintroducing ocean water. Allowing water back into the Red Sea for power generation would not be enough to refill the sea and ships would no longer be able to ply its waters as a shortcut between Europe and Asia. Roelof Dirk Schuiling, of Utrecht University and the lead author on the study estimates the dam and power plant would cost somewhere between 100 and 200 billion euros to complete. He adds; “To this you must add the much smaller costs of the dam at the north side, at the southern end of the Gulf of Suez – around 15 to 20 billion euros.” Andy Hughes, former vice president of the International Commission on Large Dams says such a massive dam is technically feasible, but unlikely to be approved. “I think the world would have to exhaust all other energy resources before going this route,” Hughes says. “The engineering is possible, but the political and ecological issues would be too difficult for people to swallow. [The authors] say themselves that the effects could be global and irreversible, politically I think this would be too difficult to achieve,” he says. By the time such a giant project could be completed, Bosshard says that the efficiency of other renewables would increase to the point that “we wouldn’t have to consider such irresponsible schemes to fight global warming”. He adds that regional ecosystems are so complex that draining the Red Sea could have unknown effects on global weather patterns and ocean currents. “We don’t really understand the effects of such a large scale project,” Bosshard says. Energy and Fuels – Learn more about the looming energy crisis in our comprehensive special report. More on these topics: